1. Field of the Invention
This invention relates to packet data networks and is in particular but not necessarily related to authentication and billing of a mobile station connecting to a mobile IP (Internet Protocol) network.
2. Description of the Prior Art
For authenticating in the Internet, a shared secret must first be provided both to the packet data network as well as to the mobile node so that the secret can be used as a basis for authentication. Then, some authentication procedure has to be executed in order to authenticate a node to another node.
RADIUS (Remote Authentication Dial In User Service) is an Internet standards track protocol described in a memo rfc2138.txt, April 1997, by C. R. Livingston, A. R. Merit, W. S. Daydreamer, and S. W. Livingston. The RADIUS protocol is designed for carrying authentication information, authorization information and configuration information between a Network Access Server which desires to authenticate its links and a shared Authentication server. Servers implementing RADIUS can support a variety of user authentication methods. When the server is provided with a user name and original password given by a user, it can support the Point-To-Point Protocol (PPP), the Password Authentication Protocol (PAP), the Challenge Handshake Authentication Protocol (CHAP), UNIX login and other authentication mechanisms.
A memo rfc2139.txt, April 1997, by C. R. Livingston deals with RADIUS accounting. Here, the RADIUS protocol is used to carry accounting information between a Network Access Server and a shared Accounting Server.